Making your own biodiesel and help save the planet

Can it be done? Well making your own diesel fuel is certainly a realistic proposition. The procedure is quite straightforward and you can reduce your fuel bill by up to 70% using a renewable/recycled product. Saving the planet is of course, a slightly more complex problem.

Biodiesel is a diesel fuel made from vegetable oil, typically from crops such as rapeseed, palm or soybean. It can also be made from waste cooking oil from restaurants, chip shops or industrial food producers.

A recent change in legislation means it is now possible to manufacture up to 2500 litres of Biofuel per year tax free.

So how do you turn it into fuel for your diesel car?

The easiest and cheapest way is to obtain a big can of cooking oil from your local cash’n’carry, tip it in the tank and press on. This method does have snags however and whilst you will probably not notice much difference initially, particularly with an older engine, you may be storing up problems for the future. These would include poor atomisation of the fuel (due to its high viscosity), incomplete combustion, coking of the fuel injectors, piston ring carbonisation and contamination of the lubricating oil.

The best thing to do is to convert the vegetable oil into Biodiesel. The most practical way to do this is using a process called base catalysed transesterification. Sounds complicated? It isn’t. You will need, in addition to your vegetable oil, a small quantity of alcohol (methanol works well, get it from your local model shop), a little sodium hydroxide (caustic soda, get it from Tesco) and some rubber gloves. And that’s about it.

Full details of the manufacturing process can be obtained from a number of sites on the Internet and if your wife won’t let you use the kitchen table, it is also now possible to purchase a “do it yourself” Biodiesel kit (a bit like a home brew kit) with full instructions including raw materials if required. So you can do it in the shed.

But will it help save the planet?

There is only enough waste cooking oil to produce about a quarter of 1% of the UK’s current demand for diesel fuel, so commercial production of vegetable oil will be necessary to make up even a small proportion of the remaining 99%.

The main benefit of Biodiesel (as with Bioethanol, the equivalent fuel for petrol engines) is that it is considered to be ‘carbon neutral’. This is because as the crop grows it absorbs the same amount of carbon dioxide (greenhouse gas) as it produces when the fuel is burnt. This argument falls down a bit however when you factor in the carbon dioxide which was already being absorbed by the plants which were growing there in the first place. It doesn’t do much for the local population in third world countries either if those plants happened to be their food. There are also a few minor considerations that need to be addressed. For example, Biodiesel is biodegradable, a useful quality in say, fast food wrappers, but a mixed blessing in motor fuel which can suffer from microbiological infestation. Biofuels also release nitrous oxide (a greenhouse gas created from the nitrates in the fertilisers) into the atmosphere. So it’s not at all straightforward. The government (you know, the organisation which gave us child centred education and democracy in Iraq) has decided to adhere to the EU directive requiring that 5% of our transport fuel should come from renewable sources by 2010. Let’s hope they know what they’re doing.